docs: def register(self, preference_class):
          """
          Store the given preference class in the registry.
  
          :param preference_class: a :py:class:`prefs.Preference` subclass
          """
          preference = preference_class(registry=self)
          self.section_objects[preference.section.name] = preference.section
  
          try:
              self[preference.section.name][preference.name] = preference
  
          except KeyError:
              self[preference.section.name] = collections.OrderedDict()
              self[preference.section.name][preference.name] = preference
  
          return preference_class